297110400 Frigidaire Refrigerator Thermister is a temperature-sensing resistor (thermistor) used in Frigidaire refrigeration appliances to convert local temperature into a measurableâ electrical resistance for the control electronics. as a passive semiconductor âsensor-typically an NTC type in refrigeration applications-it provides an analog resistance valueâ that varies predictably with temperature and is read by the appliance control board or⤠defrost controller.
Inside the refrigeratorâ system the thermister supplies the control system with real-time temperature facts âthat influences compressor cycling, evaporator fanâ operation, defrost timingand in some models the damperâ or⤠ice-maker logic. It is indeed â˘usually mounted in an air stream, on or near the evaporator assemblyor inside the âfresh- or freezer-compartmentâ to represent the compartment or coil temperature; its electrical⣠signal is âused by thermostat logic and closed-loop control algorithms to maintain setpoint, prevent coil freeze-upand sequence⢠defrost and fan operations. The sensor therefore interacts â¤directly with the main control board,temperature-control circuitry,and mechanical systems that modulate cooling and defrost activity.
In this article readers will find âŁa technical overview of the thermister’s operating principle â¤and expected behavior,guidance on â˘compatibility and how to confirm the correct part numberâ and connector⣠type for a given model,common âfailure symptoms â˘(for example open or short circuit,out-of-spec resistance causing improper cycling,false error codes,or defrost faults),practical troubleshooting methods (resistance⤠checks,temperature-resistance comparison,harness and connector inspection),and key replacement considerations â¤such as â˘correct placement,secure mounting,and verification after installation. The coverage focuses on information useful toâ technicians, engineersand⢠informed appliance owners who needâ to diagnose, testor replace this sensor in⢠a service context.
Table of Contents
- Function and Role of the Refrigerator Temperature Sensor â˘in Frigidaire Cooling control
- How the 297110400 Frigidaire Refrigerator Thermister Worksâ Inside the Appliance
- Common Failure Symptoms, âDiagnostic Tests and Expected Multimeter Readings
- Compatibility, Replacement Considerations and StepâbyâStep Installation for the â˘297110400 Sensor
- Q&A
- The Way Forward
Function and Role of the Refrigerator Temperature Sensor in Frigidaire Cooling Control
the 297110400 Frigidaire Refrigerator Thermister is an NTC-type temperature sensor used by the fridge control board to convert local⣠air temperature into an electrical resistance value. The control board continuously reads â˘that resistance and uses the sensor’s calibrated resistance-to-temperature curve to decide when to run the compressor, operate the evaporator fanand terminate defrost cycles. Placed inside the fresh-food cavityâ or on âthe evaporator inlet, the sensor provides the âcontrol logic with a localized temperature reading;â for⤠example, a rapid rise â¤in the sensed temperature âwhen the door is held open will cause the controller to run the compressor longer to restore setpoint temperature, while during defrost the controller watches âthe sensor to determine when the iceâ has âmelted⣠and it is indeed safe to stop heating.
Technically the part behaves as a âpassive resistive element whose resistance decreases as temperature increasesand it must be electrically and physically compatible with the Frigidaire control harness and calibration curve to produce correct control behavior. Practical considerations for techniciansâ include confirming mechanical fit âand connector type before replacement,measuring the sensor with a multimeter to verify continuity and âapproximate resistance at known ambient temperature,and âŁchecking wiring⣠and board inputs when diagnosing temperature-related faults. Common failure modes produce symptoms such â¤as fluctuating temperatures,⤠continuous compressor operationor premature cycling; basic diagnostic steps andâ reference values are summarized below.
- Symptoms: âŁunstable fridge temperature,frequent on/off cycles,or error codes â¤indicating sensor faults.
- Diagnostics: measure resistance at room temperature, inspect connector âŁand harness for corrosion, compare readings against the expected resistance-temperature curve.
- replacement: match part number and connector type, avoid stretching⣠sensor leads or⢠mounting in a⤠location that gives inaccurate local readings.
| Item | Description |
|---|---|
| Part | 297110400 Frigidaire Refrigerator Thermister (NTC thermistor) |
| Function | Provides temperature feedbackâ to control board for compressor, â˘fanand defrost control |
| Typical characteristic | NTC âŁbehavior – resistance decreases withâ rising temperature; exact R-T curve is model-specific |
| Commonâ diagnostics | Continuity and resistance â˘check at known ambient temperature; inspect connectors and wiring |
How the 297110400 Frigidaire Refrigerator Thermister Works Inside the Appliance
The 297110400 Frigidaire Refrigerator Thermister is a â¤negative-temperature-coefficient (NTC) resistive sensor used by âŁtheâ refrigerator control board to monitor âŁcompartment or evaporator temperature. It translates local temperature into a â¤predictable resistance value that âŁthe controller âsamples as a voltage or ADC code; as temperatureâ rises the resistance fallsand the controller applies⢠that change against itsâ temperature âlookup⢠table or control algorithm to modulate⣠compressor runtime, evaporator fan speedand defrost âsequencing. In practical terms⢠the component provides the âimmediate temperature âfeedback used to maintain setpointâ and âŁto trigger protective behaviors such as anti-short-cycle delays or initiating aâ defrost cycleâ when the evaporator temperature indicates frost⣠buildup.
Compatibility depends âŁon matching the thermistor’s â¤resistance-versus-temperature curve, connector type,â and physical mounting location so the control âŁboard âreads expected values. Technicians verify function by measuringâ resistanceâ at a known temperature and observing a monotonic change when warmed or cooled (such as, breathing âon the sensor or applying ice). Common failure â¤modes include open circuits,intermittent wiring/connectors,and drifted resistance thatâ causes incorrect temperature readings and symptoms such as continuous cooling,warm compartments,or excessive defrost runs; replacing the sensor with aâ part that matches the original resistance curve âŁand connector typically restores â¤normal control behavior.
- Symptoms of a bad sensor: erratic temperature display, compressor short-cycling, persistent warm or overcooled âŁcompartments.
- Fast bench tests: measure resistance at ambient,then warm/cool the sensor to confirm predictable NTC behavior.
- Installation ânotes: match connector and mountingâ location; avoid contaminating the sensor⢠tip or placing it⣠under adhesive that⣠insulates it from air flow.
- Diagnosticâ tip: compare readings to the service âŁmanual’s expected⣠resistance/temperature table for definitive verification.
| Item | Description |
|---|---|
| Type | NTC thermistor⣠temperature sensor (resistance âŁdecreases with increasing temperature) |
| Connector | Model-dependent â¤2âpin or multi-pin harness; must match control boardâ plug |
| Function | Provides temperature feedback for compressor control, fan controland defrost⢠logic |
| Typical failure effect | Incorrect temperature control: warm fridge, overcoolingor improper defrost timing |
Common⢠Failure Symptoms, Diagnostic Tests and Expected âMultimeter Readings
The 297110400 Frigidaire Refrigerator Thermister is a negativeâtemperatureâcoefficient (NTC) sensing âelement used by the refrigerator control board âto monitor air or evaporator temperature andâ regulate compressor, fanand â¤defrostâ cycles. In normal operation the âthermistor presents a predictable resistance â˘curve: â¤resistance decreases as temperature ârises. Electrical compatibility with a given frigidaire model depends⢠on the thermistor’s resistanceâtemperature characteristic and connector type rather than the physical appearance alone; replacing âŁwith a part that has a substantially different R-T curve can produce incorrect control behavior even if the connector fits.⣠Common failure modes include open circuit, internalâ short, slow response due to contamination or mounting issuesor âŁdrift in the R-T characteristic so the⢠controller receives âan inaccurate⤠temperature value.
Technicians diagnose the sensor with a handheld â˘digital multimeter by⤠measuring resistance and observing itsâ change with controlled temperatureâ changes. A good practice is to remove or isolate the thermistor from the harness before testing to avoid parallel circuit effects, then measure at known âtemperatures (ambient, iced water, warm âair) and⢠compare to the âexpected âcurve. A stable,repeatable â¤change⢠in âresistance with temperature confirms âŁfunctional behavior; a reading that is âeffectively infinite indicatesâ an open,and a nearâzero reading indicates a short.For inâsystem troubleshooting,⣠verify that the⣠control board sees the⢠same resistance change by measuring at the harness connector and correlate multimeter values with refrigerator temperature or a calibrated thermometer.
- Symptoms: erratic âtemperature âŁcontrol, excessive compressor run time, fridge/freezer too warm or too âŁcoldor defrost cycle failures.
- Multimeter indicators: ~10 kΊ at ~25°C (typical NTC behavior), increasing to â33 kΊ near 0°C; OL âor >1 MΊ suggests open; â0-100 Ί suggests short.
- Practical checks: measure removed vs inâcircuit, warm âthe sensor with a finger to confirm resistance fallsand compare readings to⣠service documentation for the model.
| Item | Description |
|---|---|
| Sensor â˘type | NTC thermistor (negative temperature coefficient) |
| Typical resistance @ 25°C | â 10 kΊ (verify withâ model spec) |
| Typical resistance @ 0°C | â 33 kΊ |
| Openâcircuit indication | Multimeter shows OL or >1 MΊ |
| Shortâcircuit indication | Multimeter⤠â 0-100 Ί |
Compatibility, Replacement Considerations and StepâbyâStep Installation for the 297110400⤠Sensor
The 297110400 Frigidaire Refrigerator Thermister is an NTC temperature sensor used by the refrigerator control board to monitor compartment âŁor evaporator temperatures and to sequence compressor and defrost cycles. Theâ device changesâ resistance with â¤temperature; the âcontrol board interprets that resistance using a specific thermistor curve. âWhen evaluating compatibility, match the sensor’s resistance-versus-temperature characteristic, connector style (typically a twoâpin housing), lead lengthand mounting âclip or boss location.â Replacing theâ sensor withâ a part that âhas âa different curve or âa âŁpoor mechanical fit can result âŁin incorrect temperature readings,⤠excessive run timesor âŁimproper defrost timing even if the connector fits physically.
Installation requires basic appliance service skills and a multimeter to verify function before and after replacement. Follow safe isolation procedures and verify the sensor’s behavior at â¤ambient temperatures and under controlled warming/cooling; a functioning thermistor will â˘show a predictable resistance decrease âas temperature rises. If symptoms persist after replacement, check harness continuity and controlâboard inputs as the problem can be wiring, connector corrosionor a âfailed boardâ rather than the âŁsensorâ itself.
- Disconnect power to â¤the refrigerator before any work.
- Remove â˘the access panel⤠or evaporator cover to expose the sensor; note âits orientation and clip location.
- Unplugâ the twoâpin connector and free the sensor from its clip or âbracket without pulling on the wires.
- measure resistance at room temperature with a âmultimeter (compare to service data or table below); install the new sensor in the same orientation and secure the clip.
- Reconnect the harness, restore powerand monitor temperature readings andâ compressor/defrostâ behavior for⣠one full cycle.
| Item | Description |
|---|---|
| Type | NTC thermistorâ (negative temp coefficient) |
| Typical resistance @ 25 °C | â 10 kΊ (verify withâ service documentation; values vary âby design) |
| Connector | Twoâpin housing; verify latch style andâ pin orientation |
| Mounting | Snapâin clip or screw boss near evaporator/freshâfood⣠air path |
| Common⣠failure symptom | Erratic temperature readings, sustained compressor runor temperature faultâ codes |
Q&A
What is the 297110400 Frigidaire refrigerator thermistor?
The 297110400 thermistorâ is an OEM temperature sensor used on many Frigidaire refrigerators. It is a negative-temperature-coefficient (NTC) sensor mounted in the âfresh-food or freezer compartment or on theâ evaporator. The control board readsâ the thermistor’s resistance to monitor compartment temperature and control the compressor, evaporator fan and defrost cycle.
What symptoms indicate âthe thermistor might⣠potentially be failing?
Common signs of a bad âthermistor include erratic or incorrect temperature âŁreadings, refrigerator or freezer running too âwarm or too cold, frequent orâ long compressor cycles, âshorter-than-normal runs, frost buildup on the evaporatorand service/error codes related to temperature. Intermittent failures can cause unpredictable âbehavior rather than a complete⤠shutdown.
Where âis the thermistor located and how do I accessâ it?
Location varies by⢠model â¤but the thermistorâ is typically clipped into a sensor pocket in the fresh-food section, freezer lineror near the evaporator. Access usually requires â˘removing interior shelves,covers or rear panels.Always unplug the refrigerator before opening panels or handling electrical⤠connections.
How can I test the thermistor with a multimeter?
Power off and unplug the⢠fridge,then disconnect the thermistor from the harness. Measure resistance⢠across its twoâ leads with an ohmmeter. Because it is an NTC device,the âresistance â¤should drop as temperature rises (and increase when cooled). for exact target âvalues at a given temperature consult the model’s service manual; many refrigerator thermistors are around 10 kΊ âat 25âŻÂ°C but â¤valuesâ differ by model.You can check resistance in room air, thenâ in a⢠cup of ice water to confirm the resistance changes predictably.
Can I replace â¤the thermistor myself âand what safety⢠steps should I follow?
Yes, a homeowner with basic tools â˘can replace â¤it. Safety steps: unplug the âappliance, wear gloves if needed, note or photograph connector orientation, remove the old sensor from its clip or pocket, plug in the new sensor and secure it⣠in the same location, then reassemble.Avoid damaging wire insulation or the evaporator âfins.â Ifâ you’re unsure,have a qualified technician install it.
Do I need⢠to âprogram or recalibrate⤠the fridge afterâ installing a new thermistor?
Most models do not require special programming; âonce the new thermistor isâ installed and theâ unit is powered, the control board should read the sensor automatically. if the refrigerator shows incorrect temperatures afterâ replacement, try resetting the⣠control (many models will reset by unplugging forâ 1-5 minutes or following a button-reset procedure in the service manual). If problems persist, verify wiring and sensor placement and âconsultâ the service âŁdocumentation.
Will a faulty thermistor cause excessive frost â˘or failed â˘defrost cycles?
Yes. âThe control boardâ uses thermistor readingsâ to determine evaporator temperature âand to initiate defrost cycles. If the sensor reports incorrect temperatures (too warm or too cold), âŁthe board may skip orâ mistime defrosts,⤠resulting in frost buildup on the evaporator or poor cooling performance.
Is the 297110400 thermistor interchangeable with aftermarket parts and where can I buy one?
You can âuse aftermarket replacements if they match the electrical specifications, connector type and physical mounting of⤠the OEM 297110400. For reliable operation it’s recommended to use the OEMâ part â˘or a verified âŁequivalent. Parts are sold through Frigidaire âparts dealers, applianceâ parts websitesand âsome big online retailers-verify compatibility using⢠your refrigerator model number before purchasing.
The⣠Way âForward
The 297110400 Frigidaire refrigerator thermistor plays a critical role in maintaining accurate temperature control within the appliance. As a temperature-sensing component,it provides the ârefrigerator’s control â˘system with the data âŁneeded to regulate compressor cycles,evaporator fan operation and defrost timing-functions that directly affect food safety,coolingâ consistency and energy efficiency. Proper operation of this sensor helps prevent temperature fluctuations, excessive compressor run times and uneven cooling, making it an integral part of reliable refrigerator performance.
Because a faulty thermistor can mimic or causeâ a range of symptoms-such as inconsistent temperatures, frequent cyclingor⤠defrost faults-accurate diagnosis is essential before replacement. Testing with appropriate diagnostic tools and confirming the OEM part⤠number (297110400) âensures compatibility and restores intended system behavior. When diagnosis is uncertain or replacement requires disassembly, following manufacturer â˘instructions or consulting a qualified service âtechnician helps ensure safe, effective repair and preserves the refrigerator’s⣠performance andâ longevity.
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